Research Uncovers Little-Known Impacts Of Smell, Taste On Health

The senses of smell and taste may have greater bearing on health than is generally accepted by both doctors and patients. Recent research suggests that these senses and their influence on behavior have implications for nutrition, aging, mental health, obesity, diabetes and safety. Researchers supported by the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, will be presenting their work at the International Symposium on Olfaction and Taste.

Epidemiological Studies of Taste and Smell

Scientists who study smell and taste are uncovering evidence that these senses make surprising contributions to our overall health. Genetic variations and smell and taste disorders may underlie dietary habits and impact weight, blood pressure and other risk factors for cardiovascular disease or diabetes. However, epidemiologists have conducted few studies to measure the prevalence and types of smell and taste disorders in the general population or among various age groups.

Edible Taste Strips Could Standardize Taste Testing

In order to accurately measure normal ranges of taste sensitivity by gender and age, scientists need a standardized, validated taste test. Researchers currently use various tests, each with specific limitations, in which participants rate the intensity of a taste in a liquid, flavored candy or on filter paper.

How Sweet It Is

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From the donut counter to our ever-expanding waistlines, scientists are seeking clues about what could be driving the obesity epidemic in America. While much of the research effort is focused on how the body uses and stores energy, NIDCD-supported research is uncovering valuable clues through studies on the sense of taste. Studies on sweet taste receptors are providing new evidence for biological factors that raise or lower sensitivity to sweet tastes and might stoke desire for cookies, cake, ice cream and other sweet treats. In this symposium, Steven Munger, Ph.D., of the University of Maryland School of Medicine, will present recent findings on a hormone known as glucagon-like peptide-1 (GLP-1) that appears to modulate sensitivity to sweet tastes. Scientists already knew that GLP-1 produced in the gut stimulates insulin production.

From Bitter to Sweet, It's in Our Genes

Scientists hypothesize that bitter taste receptors evolved to prevent early humans from ingesting bitter-tasting toxins commonly found in plants. Yet, in scientific taste tests, up to 30 percent of people barely recognize some bitter tastes while others seem to have a heightened sensitivity to them. Bitterness can enhance food flavor—coffee, bok choy, dark chocolate and beer are perennial favorites for this reason. Scientists are seeking to better understand our response to bitterness and its influence on diet and nutrition. In this symposium, NIDCD researcher Dennis Drayna, Ph.D., will discuss genetic studies that are helping to explain why people respond differently to bitter as well as sweet-tasting compounds. His group previously identified a gene that explains differences in bitter taste perception, and has now expanded his genetic studies to understand the range of sweet taste perception. He and his team have pinpointed genetic differences that affect sweet sensitivity in different populations.

When Chronic Sinusitis Impairs Smell

A glance down the sinus remedy aisle of your local drug store only hints at the impact of chronic sinusitis in the United States. More than 30 million Americans have chronic sinusitis, according to the Centers for Disease Control and Prevention. In addition to its vexing upper respiratory symptoms, chronic sinusitis often also diminishes the sense of smell (and, thus, flavor perception). In spite of the health consequences of this widespread condition, treatment options are limited and often ineffective. This symposium will cover several studies including clinical measurements at Monell Chemical Senses Center and Thomas Jefferson University. NIDCD-funded researchers there, led by Monell's Nancy Rawson, Ph.D., and Beverly Cowart, Ph.D., are examining people with chronic sinusitis and measuring key characteristics of their disease. These studies are expected to provide valuable insights on factors of chronic sinusitis that erode the sense of smell.

Helping Firefighters Preserve their Sense of Smell

Firefighters know they are putting theirs lives on the line when they rush into a burning building, but may not be aware of the potential risk to their sense of smell. Researchers led by Pamela Dalton, Ph.D., at the Monell Chemical Senses Center studied Philadelphia firefighters with varying years of experience and found that reduced sense of smell was associated with greater years of employment. Firefighters often do not know which chemicals might be present in a fire and are regularly exposed to a variety of chemical gases and fumes. Loss of smell will not only reduce a firefighter's quality of life, but also represents an occupational hazard as it may diminish his or her ability to smell smoke or burning wires.